I had 95% blockage in both nostrils for 2 years. Try pinching both nostrils closed and breath. This I endured for 2 years until I got a chest infection. My Doc prescribed an antibiotic that not only cleared my chest but cleared my sinus passages as well.
The polyps shrank and dried up. I blew them out into a tissue.
I have been polyp free and have 100% free flow since. No probs at all with congestion.
I have been told before that this is impossible, but it worked for me. Both nostrils are dry and 100% open for 2 years now.